Absorbent paper products are a staple of everyday life. Absorbent paper products are used as consumer products for paper towels, toilet tissue, facial tissue, napkins, and the like. The large demand for such paper products has created a demand for improved aesthetics, visual effects, and other benefits on the surface of the product, and as a result, improved methods of creating these visual effects.
Many consumers prefer absorbent paper products that have a design, or other artwork, printed thereon. For example, during specific holidays, consumers sometimes choose a paper towel product that compliments that holiday.
In the art of absorbent paper products, printed indicia may be provided onto the substrate surfaces using process printing processes which often offer an overall positive consumer response. However, typical prior art process printing methodology and apparatus for absorbent paper products is often limited to having four colors as the basis for generating the resulting color palette. The prior art process printing allows producers and manufacturers with the benefit of absorbent paper products with the ability to print on absorbent paper product substrates at a speed that is commercially viable. Those of skill in the art will appreciate that the substrates used for many absorbent paper products, especially through air dried and other formed substrates, have properties such as a relatively low modulus, a highly textured surface, and other physical properties that make such a substrate difficult to print on using conventional high-speed printing processes/apparatus. While practical, the prior art processes for printing on absorbent paper product substrates are held to a four color base for printing, and, as a result, are unable to capture as wide of a color palette as a process/apparatus that takes advantage of a larger number of base colors. Without wishing to be limited by theory, it is thought that providing an absorbent paper product with a color palette that exceeds the prior art color palette (i.e., a product having more vibrant, intricate, or bright printed pattern thereon) will delight the consumer.
Kien, US 2009-0114354 A1, discloses color gamut boundaries defined by the following system of 2-dimensional equations in CIELab coordinates (2-D gamut), respectively:{a*=−41.2 to −29.0; b*=3.6 to 52.4}→b*=4a*+168.4{a*=−29 to −6.4; b*=52.4 to 64.9}→b*=0.553097a*+68.4398{a*=−6.4 to 33.4; b*=64.9 to 42.8}→b*=−0.553097a*+61.3462{a*=33.4 to 58.0; b*=42.8 to 12.5}→b*=−1.23171a*+83.939{a*=58.0 to 25.8; b*=12.5 to −28.2}→b*=1.26398a*−60.8106{a*=25.8 to −9.6; b*=−28.2 to −43.4}→b*=0.429379a*−39.278{a*=−9.6 to −41.2; b*=−43.4 to 3.6}→b*=−1.48734a*−57.6785
where L* ranges from 0 to 100.
More specifically, Kien provides the extrapolated color gamut boundaries defined by the following system of 3-dimensional equations in CIELab coordinates (3-D gamut), respectively:
Vertexes defining each FaceVertex 1Vertex 2Vertex 3E a* + F b* + G L* + H = 0z1x1y1z2x2y2z3x3y3Face Plane Equation CoefficientsL*a*b*L*a*b*L*a*b*EFGH67.7 −33.5 46.766.733.4 42.887.6 −6.166.5−57.8 1358.7 1431.5−35396.167.7−33.5 46.787.6−6.166.593.1−5.648.8461.1−140.8 −494.955524.367.7−33.5 46.766.733.442.836−2.24.681.52089.4−2694.4 87567.167.7−33.546.736−2.24.656.4−41.2 3.6−890.5597.8−1673.2 55526.267.7−33.5 46.779.3−15.9 −15.8 56.4 −41.2 3.61206.2109.6−1239.8 119226.767.7−33.546.793.1−5.6 48.879.3−15.9−15.81611.9123.4−1780.7 168788.666.733.442.887.6−6.166.593.1−5.648.8500.3227.7687.3−72297.866.733.442.893.1−5.6 48.894.3−0.321242.7 186.71793.4−169118.266.733.442.894.3−0.3280.6 16.9−5.9777.013.0968.0−91074.466.733.442.880.616.9−5.9 65.242.4−5.7747.2100.41238.6−111862.766.733.442.865.242.4−5.752.15812.5662.794.5920.4−87567.866.7 33.442.852.15812.536−2.24.6372.51275.0 −2018.467617.093.1−5.648.894.3−0.3279.3 −15.9−15.8 723.460.8−824.477838.394.3−0.3279.3 −15.9−15.8 80.6 16.9−5.9125.4−471.7429.4−39511.479.3−15.9−15.8 80.616.9−5.959.3 −20.7−36.4−171.2 649.8−628.257356.979.3−15.9 −15.856.4 −41.23.659.3 −20.7−36.4 −859.7 −396.1614.3−68641.980.616.9−5.965.242.4−5.761.318.4−27.6 −338.0469.1−553.753104.580.616.9−5.959.3 −20.7−36.4 61.318.4−27.6126.4−757.6861.7−76057.565.2 42.4−5.752.15812.542.5 25.8−28.2−707.9571.6−48.936459.565.242.4−5.742.525.8−28.261.3 18.4−27.6−409.4 480.1−176.531599.252.15812.536−2.24.642.5 25.8−28.2−579.4−59.52195.8−80048.436−2.24.656.4−41.23.648−9.6−43.4 967.2317.01864.6−66456.136−2.24.648−9.6 −43.4 42.525.8−28.281.6384.11586.7−58709.356.4−41.23.659.3−20.7−36.448−9.6−43.4 472.3263.8300.51560.759.3−20.7−36.448−9.6−43.461.318.4−27.685.4−464.0 371.4 −37144.948−9.6−43.442.525.8−28.261.318.4−27.6289.1−624.8133.7 −30760.8
Accordingly, it is desired to provide a printing process and apparatus for providing an absorbent paper product that has a relatively wide color palette.